AUGUSTA, Ga. — The tournament was over. The final result of the 80th Masters was a forgone conclusion.

The only chore that seemingly remained for Jordan Spieth, who owned this tournament from his opening tee shot Thursday, was a trip to the Butler Cabin, where he would slip the Green Jacket over his own shoulders as the defending champion.

Then all hell broke loose around Amen Corner.

Spieth, at age 22, was poised to win his second consecutive Masters and take over the No. 1 world ranking.

And then he did neither.

When the violent tornado had finally passed through Augusta National on an unforgettable Sunday afternoon, it had turned the tournament upside down and left Englishman Danny Willett, who quietly carded a final-round 67, as the winner at 5-under par and Spieth a stunning distant runner-up at 2-under.

Everything changed for everyone involved on No. 12 — the centerpiece of Amen Corner and arguably the most famous par-3 in golf.

In one of the most shocking turns of events in Masters history, Spieth authored one of the greatest collapses in not only Masters history but in major championship history when he took a quadruple-bogey 7 on No. 12.

“It’s a stock 9-iron for me,’’ Spieth said. “I didn’t take that extra deep breath and really focus on my line on 12. Instead, I went up and I just put a quick swing on it.’’

He took a drop in the shallow portion of the 13th fairway and chunked his next shot into the middle of the water — a shot you’d expect to see from a nervous 20 handicapper afraid to hit over a water hazard.

His fifth shot landed in the back bunker and, after he splashed out and made the putt, Spieth had scored a 7 on the hole — the highest score he’s ever posted in a major championship.

“Boy, you wonder about not only just the tee shot on 12, but why can’t you just control the second shot, you know, and make 5 at the worst, and you’re still tied for the lead?’’ Spieth said. “Big picture, this one will hurt. It will take awhile.’’

Spieth carried a five-shot lead as he made the turn thanks to consecutive birdies on Nos. 6, 7, 8 and 9 and he looked in complete command.

“It was a dream-come-true front nine,’’ he said.

But he began to show signs of nerves with bogeys on No. 10 and No. 11. And then 12 happened.

“Just a lapse of concentration on 12 and it cost me,’’ he said.

It cost him a chance at history, a chance to become only the fourth player ever to defend his Masters title. Spieth, who finished second in his first Masters, in 2014, and won it last year, entered the day having owned the lead in his previous seven rounds at Augusta, a Masters record.

None of that mattered by about 7:15 p.m., when Spieth staggered off the 18th green looking like he’d just gone 10 rounds with Mike Tyson in his prime — three shots behind Willett.

“It’s all rather surreal right now,’’ Willett said.

Spieth was gutted afterward. He had converted his last five 54-hole leads into victories — two of those major championships.

“It was just a very tough 30 minutes for me that hopefully I never experience again,’’ he said.

As he stood on the 12th tee, Spieth was 5-under par and had a one-shot lead over Willett. When he walked off the 12th green, he was 1-under par trailing Willett by three shots. He made a couple of game comeback birdies on Nos. 13 and 15, but never fully recovered.

“It all happened very, very quick,’’ Willett said.

Jason Day said he was on the 15th hole when he looked at the scoreboard and saw the carnage.

“I was absolutely shocked when I saw Jordan go from 5 to 1,’’ Day said.

“Anything can happen at Augusta — especially at Amen Corner,’’ said Lee Westwood, who tied for second with Spieth at 2-under. “It’s a fine line between disaster and success at this place, and it happened to Jordan. Championship golf can throw in some shocks sometimes.’’

As if what he’d endured during the final 90 minutes of the tournament was not painful enough, taking part in the traditional Green Jacket ceremony at Butler Cabin and then on the 18th green must have felt like it took 90 days to Spieth.

“I can’t think of anybody else who may have had a tougher ceremony to experience,’’ Spieth said.
In a quiet moment during the Green Jacket ceremony, Willett, the son of a vicar in England, told Spieth that “maybe fate’’ had decided this was his time.

“I certainly wanted to control fate myself,’’ Spieth said.

The Masters so often shows even the best in the game that they cannot control their own fate. The unexpected drama is the magical beauty of this tournament.